Cold enrichment device



Aug. 16, 1960 z. ARKus-DuNTov COLD ENRICHMENT DEVICE April 29, 1957 I I l I A TTOPA/E Y United States Patentf 949,102 `Co'LD ENRIcHivrENT DEVICE Zra Arku's-Duntov, Grosse Pointe lShores, l\/ Iich., as-

signor to General Motors Corporation, Detroit, Mich., a corporation of Delaware Filed Apr. 29, 1957, Ser. No. 655,627

4 Claims. (Cl. 12S-119) This invention relates to a fuel injection control system. In particular, the present invention is an improvement in the type of mass air flow system shown and described in copending application Serial No. 608,853, Dolza, led September l0, 1956, nowv Patent No. 2,843,098.

In fuel injection systems of the mass air type it has been found that metering the quantity of fuel solely in accordance with the mass of air flow is linsufficient to provide adequate enrichment of the fuel air mixture when the engine is started orrun in a cold condition. Various mechanisms have been employed to enrich the mixture when the engine is cold including, in the aforenoted application, the use of a solenoid controlled mechanism for retaining the metering valve in a maximum fuel flow position for a timed interval afterstarting.

The present invention represents an improved enrichment device in which manifold vacuum is utilized to supplement the normal meteringv vcontrol signal. More particularly, the present device includes an engine temperature responsive device which delivers the supplementing manifold vacuum force to the metering valve control mechanism in inverse proportion to engine temperature. The present device is arranged that when the engine has warmed sufficiently, manifold vacuum has no effect on the metering control force. v

The details of the present invention as well as other objects and advantages are set forth in the description which follows.

The drawing is a diagrammatic representation of a fuel injection system embodying the subject invention.

An induction casing is shown at and includes an intake passage 12 adapted to provide air to individual cylinder mixture passages 14. A venturi 16 is formed in intake passage 12 which also includes a throttle valve 18 posteriorly disposed relative to the venturi.

A pump 20 driven at engine speed draws fuel from a reservoir 22 through a conduit 24 and delivers the fuel under pressure to a conduit 26. -A- metering control mechanism is shown generally at 28 and includes a casing portion 30 which is suitably bored at 32 to slidably receive a metering valve member 34. Casing bore 32 extends longitudinally to provide a fuel metering cavity 35. A port 36 is formed in casing 30 and communicates with fuel conduit 26 to continuously flow fuel under pressure through a filter 38 disposed in casing 30 to a counterbored chamber 40 and cavity 35.

A check valve I42 is disposed in chamber 40 to prevent any backing up of fuel vapors. In the present instance the valve is biased closed by a spring 44. Although an excess spring tension is not desirable the spring 44 should maintain sufficient pressure in the upstream portion of this system to reduce the formation of any vapors.

A passage 46 is formed in casing 30 and communicates with reservoir 22 through a conduit 48. The metering valve 34 includes a tapered end portion 50 which coacts with the metering cavity 35 and passage 46 to control the quantity of fuel which is bypassed through the passage and returned to the reservoir 22.

ICC

A pluralityY of radial pasasges 52 are formed in casing 30 and connect withvconduits 54 to deliver metered fuel to the individual cylinder intake passages 1'4 proximate th'e inlet valves 56. Itis apparent that the quantity of fuell delivered vto conduits54 is determined by the quancasing members 66 and 68. Spring elements 70 and 72 respectively coact w-ith the diaphragm and casing members. 66 and 68 to normally bias the diaphragm in a lowered position in which the metering valvev 3'4 is conditioned for a maximum bypass of fuel.

The chamber 7=4 defined. bycasing 66 and diaphragm 64,-communicates through a conduit 76 with the throat of the venturi 16. Thus a vacuum force is created in chamber 74 which is proportional to the mass of air flowing through intake passage 12. The chamber 78 defined by diaphragm 64 and casing 68 communicates through a conduit 80 with the intake passage 12 anteriorly of venturi 16and is maintained at substantially atmospheric pressure, ignoring for present purposes the pressure effects of air velocity and barometrical changes.

During normal operating conditions variations in vacuum in chamber 74 and the pressure of fuel in the metering cavity 35 differentially position the meter valve 3'4 to provide the proper fuel flow to the engine cylinders. When-starting or running the engine cold, however, it is necessary to enrich the fuel-air ratio to realize satisfactory engine operation. To this end, the present device includes a passage 82 formed in the air intake casing 10 which communicates with the induction passage 12 posteriorly ofthe throttle 18. Passage 82 is communicated through suitable conduits with the venturi vacuum conduit 76. Thus, under conditions to be described, manifold vacuum is adapted to supplement the metering controlv force acting on diaphragm 64 to control the metering valve 34.

An engine temperature responsive device is shown generally at 84 and includes a casing 86 within which a thermostatic coil element 88 is disposed. One end of the coil 88 isv adapted to be suitably anchored to the casing 86 and the other end fixed to one arm 90 of a bifurcated lever 92. Lever 92 is secured to a shaft 94 rotatably mounted in casing 86. A lever 96 is lfixed to shaft94 and is articulated through a link 98 to a slidable valve member 100 disposed in a valve casing 102. A cylinder 104 is formed in casing 86 and has a piston 106`slidably disposed therein. A passage 108 and a conduit 110 communicate the cylinder to the intake passage 12 posteriorly of throttle 18 whereby manifold vacuum acts on the piston 106. The piston 106 is suitably articulated Ito the other arm 112 of lever 92.

Casing 102 includes a port 114 communicated with manifold vacuum passage 82 through a conduit 116. The casing also includes an outlet pont 118 connected through conduits 120 and 122 Ito the venturi vacuum passage 76.

The thermostatic element 88 when cold is adapted to rotate the shaft 94 and lever 92 in a counterclockwise direction moving the slidable valve element 100 to uncover port 114 permitting manifold vacuum to be transmitted to venturi vacuum passage 76. Manifold vacuum acting on piston 106 opposes the action of the thermostatic element and tends to urge the valve member in a direction yto cut off the flow of manifold vacuum to the metering chamber 74. Thus with the engine cold device 84 will position the valve 100 such that manifold vacuum supplements the venturi vacuum to maintain the diallil-"patented Aug. l'16, 1960 Y phragm 64 in an upper position thereby reducing the quantity of fuel bypassed by the metering valve 34 and enriching the fuel-air mixture. As the thermostat warms the resistance of element 88 decreases and manifold vacuum acting on piston 106 will gradually move the valve member 100 to reduce thesupplementing manifold vacuum force until such time as the valve completely cuts off manifold vacuum leaving .the metering control function completely to venturi vacuum. By this means a modulation of the manifold vacuum force is obtained permitting a gradual transition from an enriched to a normal fuel-air ratio.

A conduit 121 is connected to a port 123 in casing 86 and is coiled about, or otherwise exposed to, the exhaust manifold 124. Controlled leakage around piston 106 will maintain a vacuum in casing 86 and, since end 125 of conduit 121 is open to atmosphere, air heated to engine temperature will be drawn through the casing. In this manner thermostatic element 88 will accurately reflect engine temperature.

A needle valve 126 is threadably mounted in intake casing for the purpose of adjusting the magnitude of manifold vacuum in conduit 116. Further, an additional needle valve 128 is provided in a casing 130 intermediate the valve 100 and the venturi vacuum conduit 76. Needle valve 128 adjustably determines the supplemental vacuum force provided through the temperature responsive mechanism 84. lt is apparent, particularly with regard to the needle valve 12S, that a xed orice might be substituted therefor if desired.

Various modications of the subject invention are possible within the intended scope as set forth in the appended claims.

l claim:

1. A fuel injection system for an internal combustion engine comprising an air induction passage, a venturi in said passage, a throttle valve in said passage posterior to said venturi, a source of fuel under pressure, conduit means for communicating said fuel source with the cylinders of said engine, a valve disposed intermediate said fuel source and said conduit means for metering the quantity of fuel owing to said cylinders, a device for controlling said metering valve, first conduit means communicating said venturi with said control device to normally position the metering valve in accordance with the mass of air flowing through the induction passage, second conduit means communicating said control device with the induction passage posteriorly of said throttle, valve means in said second conduit means for conveying manifold vacuum to said control device, a temperature responsive element connected to and tending to open said valve means, and a manifold vacuum responsive element also connected to and tending to close said valve means whereby the manifold vacuum force acting on the control device is inversely proportional to engine temperature.

2. A fuel injection system for an internal combustion engine comprising an air induction passage, a venturi in said passage, a throttle valve in said passage posterior to said venturi, a source of fuel under pressure, conduit means for communicating said fuel source with the cylinders of said engine, a valve disposed intermediate said fuel source and said conduit means for metering the quantity of fuel owing to said cylinders, a device for controlling said metering valve, first conduit means communicating said venturi with said control device to normally position the metering valve in accordance with the mass of air flowing through the induction passage, second conduit means communicating manifold vacuum with said control device, valve means in said second conduit means for modulating the manifold vacuum delivered to said control device, engine temperature and load responsive means adapted to actuate said valve means whereby the manifold vacuum in said second conduit means is inversely proportional to engine temperature, and flow restricting means in said second conduit means anteriorly and posteriorly of said valve means.

3. A fuel injection system as set forth in claim 2 in which said restricting means comprises a first adjustable valve intermediate the induction passage and valve means, and a second adjustable valve intermediate the valve means and said first conduit.

4. A fuel injection system for an internal combustion engine comprising an air induction passage, a venturi in said passage, a throttle valve in said passage posterior to said venturi, a source of fuel under pressure, conduit means for communicating said fuel source with the cylinders of said engine, a valve disposed intermediate said fuel source and said conduit means for metering the quantity of fuel flowing to said cylinders, a device for controlling said metering valve, rst conduit means communicating said venturi with said control device to normally position the metering valve in accordance with the mass of air flowing through the induction passage, second conduit means communicating said control device with the induction passage posteriorly of said throttle, valve means in said second conduit means for conveying manifold vacuum to said control device, a temperature responsive element connected to and tending to open said valve means, and a manifold vacuum responsive element also connected to and tending to close said valve means whereby the manifold vacuum force acting on the control device is inversely proportional to engine temperature, andconduit means coacting with a source of engine heat to ow heated air across said temperature responsive element.

References Cited in the file of this patent UNITED STATES PATENTS 2,378,037 Reggio June 12, 1945 2,402,332 Lee June 18, 1946 2,414,322 Mock Ian. 14, 1947 

